Process for chlorine addition



tates This invention relates to a new and improved process for preparingglycerol 1,2-dichlorohydrin by the addition of chlorine to allylalcohol. The dichlorohydrin is useful for a variety of purposes, forexample, being readily convertible to epichlorohydrin, employed for themanufacture of epoxy resins, or to glycerine.

The chlorination of allyl alcohol to yield glycerol 1,2-dichlorohydrinhas been described, but prior methods were characterized by low yields.Thus, Huntress, Organic Chlorine Compounds, John Wiley and Sons, NewYork, N.Y., 1948, p. 798, stated that chlorination of aqueous allylalcohol gives only a 20% yield of the dichlorohydrin. According toTornoe, Ben, 24, 2670 (1891), the chlorination of dry allyl alcohol withdry chlorine also gives only a 20% yield of glycerol 1,2-dichlorohydrin.A marked improvement in yield was recorded by King and Pyman, J. Chem.Soc., 105, 1238 (1914), who chlorinated allyl alcohol in a carbondisulfide solution and obtained a 40% yield of the dichlorohydrin. Thusthe addition of chlorine to allyl alcohol has generally been consideredan unsatisfactory reaction for practical use. For example, Williams,American Institute of Chemical Engineers, Transactions, 37, 171 (1941)stated,

The ease of allyl alcohol production established, attention was turnednext to converting it to glycerol. Direct addition of chlorine to theanhydrous alcohol to give glycerol dichlorohydrin in good yield hasnever been very successful with other workers and our attempts over awide range of conditions brought no great additional hope.

It has been the main object of this invention to provide an improvedprocess for the addition of chlorine to allyl alcohol. Further objectshave included the provision of such a process whereby dichlorohydrin isreadily obtained at high yields and the provision of an uncomplicatedprocess which can be carried out quickly and economically.

The foregoing and other objects are accomplished in accordance with thisinvention by eifecting the addition of chlorine to allyl alcohol in thepresence of certain proportions of concentrated aqueous hydrochloricacid to result in yields of 50 to over 70% of glycerol1,2-dichlorohydrin.

For best results, the addition of chlorine to the allyl alcohol iscarried out in the presence of about 0.1 to 3.5 parts by weight of waterper part of allyl alcohol and in the presence of sufficient HCl to forman aqueous solution containing 15 to 45% by weight of hydrogen chloride.In other words, the addition of chlorine to allyl alcohol is bestcarried out by providing a solution of allyl alcohol containing about0.15 to parts by weight of to 45% aqueous hydrochloric acid per part byweight of allyl alcohol. The preferred solution is one containing 1 to 3parts of 25 to 40% aqueous HCl per part by weight of allyl alcohol. Thechlorination may be carried out at a temperature of about 5 C. to 35 C.,the range of to C. being preferred. While the addition of chlorine maybe carried out in the presence or absence of light or ultra-violetradiation, the reaction is preferably eflected in the absence of light.

While metallic chlorides may be used in conjunction with the hydrogenchloride, this is not the preferred practice due to resultingcomplications caused by limited solubility or in product isolation. Thedichlorohydrin atent 3,037,059 Patented May 29, 1962 Example 1 Athree-necked round bottomed flask was equipped with a mechanicalstirrer, an adapter containing a thermometer and reflux condenser, andin the third opening a gas inlet tube. A solution of 29 parts of allylalcohol in 118 parts of 37% aqueous hydrochloric acid was prepared andstirred. Liquid chlorine was condensed and 35.5 parts weighed into asmall one-necked round bottomed flask which had previously been cooledin Dry Ice. The liquid was then allowed to vaporize from the small flaskinto the stirred solution through the gas inlet tube. The tempera tureof the solution was maintained at 20-25 C. while the reaction wascarried out in the presence of diffuse sun light. After chlorineaddition, the clear colorless solution was extracted three times with125 parts of ethylene dichloride each time. Fractionation of thecombined extracts gave, after removal of the solvent, 35 parts (55.2%yield, based on allyl alcohol) of colorless glycerol 1,2-dichlorohydrin,B.P. 70-80 C./ 15 mercury pressure.

Example 2 The procedure of Example 1 was repeated, using the samequantities and conditions, except that the chlorine addition was carriedout in the presence of ultraviolet light. On fractionation, 38 parts ofproduct were obtained, representing a 59% yield of dichlorohydrinn, B.P.6870 C./15 mm.

Example 3 Parts Cut 1: B.P. 4070 C./200-15 mm. 116 Cut 2: B.P. 7082C./15 mm. 79 Cut 3: B.P. 83-l15 C./15 rnm. 6 Cut 4: B.P. 1l5120 C./15mm. 5

The yield of glycerol 1,2-dichlorohydrin was 79 parts (61% yield).

Example 4 A solution of 58 parts of allyl alcohol and 11.8 parts of 37%aqueous hydrochloric acid was chlorinated, as in the above examples, indiffuse sunlight at 2025 C. Fractionation gave the following cuts:

Cut 1: B.P. 2570 C./l5 mm-" 17 parts. Cut 2: B.P. 73-87 C./15 mm--- 65parts, n =l.4826. Cut 3: B.P. 85115 C./l5 mm 4 parts, n =1.4795.

The yield of glycerol 1,2-dich1orohydrin was 65 parts (50.5% yield).

Example 5 The procedure of Example 4 was followed except that light wasexcluded from the chlorination flask by completely covering withaluminum foil. Fractionation of the reaction mixture gave the followingcuts:

Cut 1: B.P. 30-70 C./15 mm.

12 parts. Cut 2: B.P. 70-85 C./15 mm.

74 parts, n =l.4827. Cut 3: B.P. 85ll5 C./15 mm.

5 parts, n =1.4800.

Cut 4: B.P. 115-165 C./ mm.

13 parts, n =l.4912.

The glycerol 1,2-dichlorohydrin product amounted to 74 parts (57.2%yield).

Example 6 A solution of 58 parts of allyl alcohol in 118 parts of 37%aqueous hydrochloric acid was chlorinated with 71 parts of chlorine inthe absence of light at -25 C. The following fractions were obtained ondistillation:

Cut 1: B.P. 5080 C./l50 mm.

115 parts (two layers present). O1t2: B.P. 4567 C./15 mm. 1 part. Cut 3:B.P. 6980 C./l5 mm.

77.5 parts. Cut 4: B.P. 801l5 C./15 mm. 5 parts. Cut 5: B.P. 115l21C./15 mm.

7 parts.

As some glycerol 1,2-dichlorohydrin distills with water, cut 1 wasextracted with ethylene dichloride and the extract was fractionated.This yielded an additional 13 parts of product, B.P. 68-74 C./l5 mm. Theamount of dichlorohydrin was 90.5 parts (70.0% yield).

Example 7 A solution was prepared of 58 parts of allyl alcohol and 109parts of aqueous hydrochloric acid containing 22 parts of HCl.Chlorination was carried out in the dark with 71 parts of chlorine at20-25 C. Extraction of the solution three times with 125 parts ofethylene dichloride each time gave, on fractionation, 65 parts ofdichlorohydrin, B.P. 68-80 C./ 15 mm. representing a 50.3% yield.

Example 8 A total of 142 parts of chlorine was introduced into a stirredsolution consisting of 116 parts of allyl alcohol and 118 parts of 37%aqueous hydrochloric acid while the reaction mixture was maintained inthe dark at 20- C. The solution was extracted first with 725 parts ofethylene dichloride and then with 125 parts of ethylene dichloride. Theaqueous phase was mixed with 116 parts of allyl alcohol and chlorinatedunder the same conditions with 142 parts of chlorine. The reactionmixture was extracted three times with a total of 975 parts of ethylenedichloride. Fractionation of the combined organic extracts gave thefollowing cuts:

Cut 1: B.P. 4045 C./200 mm.

Ethylene dichloride. Cut 2: B.P. 40-68 C./200-15 mm.

24 parts, n =1.4414. Cut 3: B.P. 69-82 0/15 mm.

306 parts, n =1.4825. Cut 4: B.P. l10l25 C./l5 mm. 16 parts, n =1.4795.Cut 5: B.P. 125-150 C./15 mm.

18 parts, n =1.4855. Cut 6: B.P. ISO-180 C./l5 mm. 21 parts, n =1.4920.Residue: 34 parts.

Cut 3 represented a 59.2% yield of glycerol 1,2-di-- chlorohydrin.

1; Example 9 While the temperature was maintained at 20-25 C., a stirredsolution of 116 parts of allyl alcohol, dissolved in 295 parts of 37%aqueous hydrochloric acid, was treated with 142 parts of chlorine in thedark, The resulting solution was extracted four times with ethylenedichloride, employing a total of 775 parts. The aqueous phase was thenused as a chlorination medium for another 116 parts of allyl alcohol and142 parts of chlorine. This solution was in turn extracted with a totalof 775 parts of ethylene dichloride. The aqueous phase was againrecycled for the chlorination of 116 parts of allyl alcohol with 142parts of chlorine. Extraction was carried out five times with a total of875 parts of ethylene dichloride. The volume of the aqueous phase hadincreased from an initial volume of 250 ml. to 309 ml., but dilutionwith 500 ml. of water followed by the addition of solid sodium carbonateuntil the pH was 7, liberated 60 ml. of organic liquid (ethylenedichloride solution) which was combined with the previous extracts.Fractional distillation of the organic solution gave the following cuts:Cut 1: B.P. 40-50 C./200 mm.

Ethylene dichloride. Cut 2: B.P. 40-70 C./1520 mm.

13 parts, n =1.4420. Cut 3: B.P. 70-85" C./l520 mm.

537 parts, n =l.4827. Cut 4: B.P. 86-120 C./1520 mm.

28 parts, n =l.4769. Cut 5: B.P. -140 C./15 mm. 8 parts, n =l.4810. Cut6: B.P. ISO-200 C./15 mm.

49 parts, n =1.4936. Residue: 9 parts.

Glycerol 1,2-dichlorohydrin product amounted to 537 parts (69.3% yield).

Example 10 The procedure of Example 9 was followed, except that theaqueous phase was recycled four times, for a total of five runs. Thevolume of the aqueous phase rose from 250 ml. to 355 ml., but dilutionwith 500 ml. of water followed by neutralization with sodium carbonateliberated 58 ml. of ethylene dichloride solution which was added to thecombined extracts. Fractionation of the extracts produced the followingfractions:

Based on cut 3, the yield of glycerol 1,2-dichlorohydrin Cut 2:

Cut 3:

Cut 4:

Cut 5:

Cut 6:

Cut 7:

was 69.5%. Analysis of the product yielded the following value:

Percent 01 OH No.

Calculated 55. 04 435. 5 Found 54. 421. 0

Based on chlorine analysis, the purity was 98.4% and on hydroxyl number96.9%.

Example 11 A solution of 116 parts of allyl alcohol in 590 parts of 37%aqueous hydrochloric acid was chlorinated, with stirring, in the absenceof light at 20-25 C. with 142 parts of chlorine. The solution wasextracted five times with a total of 835 parts of ethylene dichloride.The aqueous phase was then employed for four more identicalchlorinations. Fractionation of the combined extracts plus additionalsolution (131 ml.) recovered from dilution and neutralization of theaqueous phase with sodium hydroxide gave the following cuts:

Cut 1: B.P. 4045 C./200 mm.

Ethylene dichloride.

B.P. 45-70 C./200-15 mm.

12 parts, n =1.4590. B.P. 70-82 C./1520 mm.

928 parts, n =1.4825. B.P. 82-1l5 C./1S mm.

85 parts, n =l.4796. B.P. 115-130 C./15 mm.

7 parts, n =1.4782. B.P. l30-150 C./l5 mm.

3 parts, n =1.4856. B.P. ISO-175 C./l5 mm.

44 parts, n =1.4930. Residue: 32 parts.

928 parts of glycerol 1,2-dichlorohydrin were obtained, (7 1.9% yield).

Cut 2:

Cut 3:

Cut 4:

Cut 5:

Cut 6:

Cut 7:

Example 12 The procedure of Example 11 was followed except that thechlorination was conducted at -5 C. and chloroform was employed as thesolvent for extraction. The yield of glycerol 1,2-dichlorohydrin B.P.69-8l C./15 mm., n =1.4826, was 946 parts or 73.3%.

Example 13 The procedure of Example 11 was followed except that thetemperature of chlorination was maintained at 30-35 C. and theextraction was carried out with carbon tetrachloride. The amount ofglycerol 1,2-dichlorohydrin, B.P. 69-83 C./ 15-20 mm., n =1.4829, was901 parts, representing a 69.8% yield.

Example 14 This example duplicated Example 11, except that thechlorination was carried out at 15-20 C. in the dark and propylenedichloride was employed as the organic liquid for extraction of thedichlorohydrin. Fractionation produced 908 parts (70.3% yield) ofglycerol 1,2-dichlorohydrin, B.P. 7l-86 C./'15-20 mm., n =1.4829.

Example 15 Hydrogen chloride gas was passed into 1,180 parts of stirred37% aqueous hydrochloric acid, cooled to to 0 C. until the weightincreased to 1240 g., providing a 40% hydrochloric acid solution. Tothis cold solution was added 232 parts of allyl alcohol. Chlorinationwas allowed to proceed in the dark by the vaporization of 284 parts ofliquid chlorine into the stirred solution while maintaining thetemperature at 5 to 0 C. After the addition, the solution was extractedfive times with a total of 1,336 parts of methylene dichloride. Theaqueous 6 portion was diluted with 750 parts of water and slowlyneutralized by the gradual addition of a 40% sodium hydroxide solution.An additional 74 ml. of organic liquid was then separated and combinedwith the methylene dichloride extracts. Fractionation of the extractsproduced the following cuts:

Cut 2:

Cut 3:

Cut 4:

Cut 5:

Cut 6:

Percent 01 OH No.

Calculated 55. 04 435. 6 Found 54. 20 428. 0

While a slight excess of either allyl alcohol or chlorine, up to about10%, may be employed in the process of this invention, the use ofsubstantially equimolar proportions is preferred as providing the bestresults. The exothermic reaction yielding the 1,2-dichlorohydrin is veryrapid, and generally the rate of chlorine addition is so chosen that thetemperature of the reaction mixture does not exceed the desired value.The total reaction time may be reduced to ten to thirty minutes or lessby the provision of adequate cooling of the reaction mixture. Also, theprocess may be carried out in continuous manner, if desired.

As modifications of the illustrative details will be apparent to thoseskilled in the art, the invention is to be considered as limited only bythe features set forth in the following claims.

What is claimed is:

1. In the preparation of glycerol dichlorohydrin, the process comprisingreacting substantially equimolar proportions of allyl alcohol andchlorine at a temperature of about 5 C. to 35 C. in the presence of 0.15to 5 parts of a solution consisting essentially of about 15% to 45% byweight aqueous hydrochloric acid per part by weight of allyl alcohol.

2. In the preparation of glycerol dichlorohydrin, the process comprisingreacting substantially equimolar quantities of allyl alcohol andchlorine at a temperature of about 20 C. to 25 C. in the presence ofsubstantially 1 to 3 parts of a solution consisting essentially of about25% to 40% by weight aqueous hydrochloric acid per part by weight ofallyl alcohol.

References Cited in the file of this patent De la Mare et al.: J. Chem.Soc. (London), 1954, pages 3990-5.

1. IN THE PREPARATION OF GLYCEROL DICHLOROHYDRIN, THE PROCESS COMPRISINGREACTING SUBSTANTIALLY EQUIMOLAR PROPORTIONS OF ALLYL ALCOHOL ANDCHLORINE AT A TEMPERATURE OF ABOUT -5*C. TO 35*C. IN THE PRESENCE OF0.15 TO 5 PARTS OF A SOLUTION CONSISTING ESSENTIALLY OF ABOUT 15% TO 45%BY WEIGHT AQUEOUS HYDROCHLORIC ACID PER PART BY WEIGHT OF ALLYL ALCOHOL.